Hearing aid devices are well known. Generally, they can be described as comprising a housing for containing operative sound transmission components such as a microphone, an amplifier, a control (or trimmer) for adjusting the volume, a transducer, and a battery. Basically, the devices operate by receiving sound via the microphone, amplifying the signals, and transmitting them via the transducer into the ear canal toward the tympanic membrane (i.e., the ear drum). An output or speaker tube may project from the hearing aid for channeling or radiating the sound from the transducer into the ear canal. FIG. 1 shows a schematic of the human ear which is helpful in understanding the use and operation of hearing aid devices generally and the inventive device and method in particular.
Referring to FIG. 1, the regions of the external ear 6 and middle and inner ear 8 are divided by dashed line E--E. Conventional hearing aid devices have been placed in and supported substantially by the concha 12, a depressed region within the external ear 6. Generally, the device itself will cover the external acoustic meatus 24, at the opening of the ear canal 26, and may be at least partially seated within the ear canal 26 itself. The microphone for the hearing aid device may be at the external ear, proximal the concha 12, and the output or speaker tube of the hearing aid may protrude within the ear canal, orientated toward the tympanic membrane 28. This membrane operates in conjunction with various bony structures, canals, nerves and nerve endings, shown generally at region 18, which function to enable one to perceive sound. The ear canal 26 is surrounded by a region of cartilage 14 and a bony region 16.
A difficulty encountered with many conventional hearing aid devices relates to fitting the device in the ear canal and the production of acoustic feedback. When there is a gap between the walls of the device and the ear canal, acoustic feedback may result, e.g., sound waves may travel back to the microphone of the device to be re-broadcast through the speaker tube. A cycle of sound may build up, and the feedback causes a loud ringing or whistling noise in the user's ear which is annoying and interferes with the ability to perceive sound. Thus, for this and other reasons it is important that there be a snug but comfortable fit between the device and the ear canal wall. Molds have been made of users' ear canals to provide devices having exterior surfaces providing custom-made fits. These individually-designed devices naturally require a number of visits to the hearing aid dispenser's office, and also, the process of making the molds may cause discomfort. Also, although such conventional hearing aids may project within, and be custom-made to fit, the ear canal, they are supported primarily if not entirely by regions of cartilage, e.g., region 14, not bone, e.g., region 16. With movements in the jaw or during conversation, the dimensions at the cartilage portion 14 may change, which alters the fitting of the device and makes it difficult to securely fit the device in the ear. Changes in the size of the ear canal also may occur with swelling, inflammation, or the accumulation of cerumen, thereby at least partially dislodging the device.
Many efforts have been made to address these problems relating to the fitting of hearing aids and acoustic feedback. A new generation of hearing aid devices have been developed that sit within, and are supported in large part by, the bony portion 16 of the ear canal. See, e.g., U.S. Pat. No. 5,395,168 issued Mar. 7, 1995 to Leenen, "In the Ear Hearing Aid Having Extraction Tube Which Reduces Acoustic Feedback" (the "Leenen patent"). These hearing aids also have drawbacks, however; for example, extracting the devices from the inner ear may pose difficulties for users, who often are senior citizens with reduced dexterity particularly in handling small objects. The Leenen patent describes a device and method for seeking to make it easier to extract an in-the-ear device from the ear. Another difficulty associated with in-the-ear devices relates to user discomfort associated with the making of molds and use of the devices.
Other approaches for improving the fit of hearing aid devices have included attaching foam pieces to the devices with use of adhesives or elongated jelly or liquid-filled pouches. See, for example, the devices described in the following U.S. patents, all of which are incorporated herein by reference: U.S. Pat. No. 5,682,020 issued Oct. 28, 1997, to Oliveira, "Sealing of Hearing Aid to Ear Canal" (the "Oliveira patent"); U.S. Pat. No. 5,002,151 issued Mar. 26, 1991 to Oliveira et al., "Ear Piece Having Disposable, Compressible Polymeric Foam Sleeve"; and U.S. Pat. No. 4,006,796 issued Feb. 8, 1977 to Coehorst, "Ear Piece Which Substantially Consists of a Thin-Walled Flexible Capsule Filled With a Liquid Medium." A recent approach for improving the fit involves providing a range of differently-sized flexible collars to be attached to the end of the device for protruding into the ear canal, wherein the wearing comfort of the user is sought to be optimized by selection of an appropriately-sized collar, as described in U.S. Pat. No. 5,742,692 issued Apr. 21, 1998 to Garcia et al, "In-the-Ear Hearing Aid With Flexible Seal" (hereinafter the "Garcia patent"), also incorporated herein by reference.
As may be appreciated from the foregoing, those concerned with hearing aids and with the comfort and well-being of individuals using them continually search for new designs and components to better fit the devices in the ear, simplify their use and operation, improve the comfort of users, and reduce feedback. It indeed would be advantageous to have an improved hearing aid device and method for fitting and/or sealing the device within the ear. Such and other advantages of this invention are described more fully with the description given below.